Author(s): CAO Shi-yue, ZHANG Jing-ping, ZHANG Yan-yan, ZHU Wan
Pages: 485-492
Year: 2017 Issue:  5
Journal: Clinical Journal of Medical Officer
Keyword:  Acinetobacter baumannii; Multidrug resistance; Extensive-drug resistance; Drug sensitivity; Combination application of antibacterial agents;
Abstract: Objective To investigate the combination of antibacterial agents which was used,the optimized therapeutic regimens were screened and effective therapy was established for broad drug resistant acinetobacter baumannii,which provided a basis for a reasonable application of antimicrobial agents in clinic.Methods The samples of the hospitalized patients who were admitted between 2013 and 2014 were collected and clinical data were collated.The bacteria were isolated and cultured from the collected samples and 50 strains of acinetobacter baumannii were screened.The minimal inhibitory concentrations(MIC)of the antibiotics were measured using the agar double dilution method recommended by the Clinical and Laboratory Standards Institute(CLSI).The common drugs were selected according to"Chinese Expert Consensus for the Diagnosis,Treatment,Prevention and Control of Acinetobacter baumannii"and"The Interpretation of Chinese Expert Consensus for the Diagnosis,Treatment,Prevention and Control of Acinetobacter baumannii"and the drug resistance of the antibiotics was analyzed according to the critical concentration standard antimicrobial drugs issued by CLSI.On the basis of the drug-resistance analysis of acinetobacter baumannii,40 isolates of multi-drug resistant acinetobacter baumannii strains were screened.The 7 antibacterial agents and 5 regimens of combined antibiotics application were assayed for drug sensitivities,respectively.The five combined antibiotics application regimens included tigecycline plus cefoperazone/sulbactam;polymyxin plus minocycline;polymyxin plus imipenem;polymyxin plus doripenem and tigecycline plus imipenem.The inhibitory effects of alone or combined antibiotics application on acinetobacter baumannii were compared.Results The 50 strains of Acinetobacter baumannii with intact clinical data were isolated in 2013-2014,which were mainly distributed to the intensive care units(ICU),the neurosurgery and general surgery departments.The 50 strains of acinetobacter baumannii were divided into 10 strains of non-multidrug-resistant acinetobacter baumannii and 40 strains of multidrug-resistant acinetobacter baumannii,among which 10 strains of extensively-drug resistant acinetobacter baumannii were included,according to the values of drug sensitivity test.The rate of drug-resistance for the isolates of acinetobacter baumannii were the lowest to both minocyline and tigecyline,all were zero.Rate of drug-resistance in two year for the isolates to polymyxin was 20% and 16%,respectively.The rate of drug-resistance of other antibiotics was over 50%.The rate of drug-resistance of levofloxacin in two year was 56% and 64%,respectively.The rate of drug-resistance of both cefoperazone/sulbactam(2:1)in 2014 and imipenem in 2013 were 96%,which were the maximum among different antibiotics tested in this study.In the experiment of combined application of antibacterial agents,the results showed that the synergistic effect accounted for 7.5%,partially synergistic effect accounted for 30% and indifference effect accounted for 62.5% in the group of tigecycline plus cefoperazone/sulbactam.In polymyxin plus minocycline group,the synergistic effect,partially synergistic effect and indifference effect accounted for 22.5%,27.5% and 50%,respectively.In polymyxin plus imipenem group,the synergistic effect,partially synergistic effect and indifference effect accounted for 55.0%,22.5% and 22.5%,respectively.In polymyxin plus doripenem,the synergistic effect,partially synergistic effect and indifference effect accounted for 12.5%,67.5% and 20%,respectively.In tigecycline plus imipenem group,the synergistic effect,partially synergistic effect and indifference effect accounted for 32.5%,40% and 27.5%,respectively.No antagonistic effect was observed.In the experiments of alone or combined application of antibacterial agents to 30 strains multi-drug resistant acinetobacter baumannii,the results showed that the all of MICs in drug combination groups were reduced,compared with that in corresponding drug used alone(P<0.01).The differences between drug combination groups and corresponding drug used alone were analyzed statistically by students′-test and p-values were found to be significant(P<0.01,for all groups).In the experiments of alone or combined application of antibacterial agents to 10 strains extensive-drug resistant acinetobacter baumannii,the results showed that the MICs in drug combination groups were reduced,compared with that in corresponding drug used alone,except that MICs between the tigecycline used alone and tigecycline plus cefoperazone/sulbactam group were found to be no statistically significant(P>0.05).The differences between other drug combination groups and corresponding drug used alone were found to be statistically significant(P<0.01).Conclusion In 50 strains of Acinetobacter baumannii isolated from our hospital between 2013 and 2014,the results of drug-sensitivities suggested that the sensitive rates to both tigecycline and minocycline were 100%,the sensitive rate of polymyxin was 82%,which was at high level.Amikaxin and imipenem had a higher drug resistant rates that reached 56% and 90%,respectively.In the treatment of acinetobacter baumannii,cefoperazone/sulbactam(1∶1)was superior to cefoperazone/sulbactam(2∶1),while both of them also had a higher drug resistant rate.The results of combined antibacterial agents showed that the FIC values of polymyxin plus imipenem and tigecycline plus imipenem groups were lower than the other groups of combinations antibiotics application regimens and the two groups showed a better synergistic effect.